Containers holding both solid and liquid materials are often used in industry. Frequently, the solid materials in these containers are denser than the liquid materials and collect at the bottom of the container. In many instances it is desirable to monitor the level of these solid materials; however, measuring the depth of solids at the bottom of a flooded bin can be difficult, impractical or inaccurate. One obstacle may be that the liquid materials are volatile and/or instable, which may make it unsafe for manual measurements and processes requiring human control. Further, properties of the solid material may prove to be a hindrance to accurate measurements. Yet another obstacle may be the geometry of the bin.
Measurement systems have been developed to attempt to provide accurate and reliable readings of the level of solids in a flooded bin. One method includes dropping a weight connected to a measuring line into the flooded bin to measure the depth at which the weight stops sinking due to contact with solid materials. This method, however, may be unreliable as the accuracy depends on properties of the solid materials and/or liquid. Loose solids may simply “swallow” the weight thereby giving a false reading of the solid level. In addition, dropping a weight typically requires human control or manipulation. If the liquid in the flooded bin is volatile and unsafe, this approach may present hazards to the operator.
Another conventional measurement system includes taking sonography readings on the side of the bin from outside of the bin. However, this type of method may provide inaccurate results for conical bins that empty from the bottom. As such, the level of solids along the sides of the conical bin may be higher than the bin center, which could skew the readings. Another similar measurement method is taking thermographic or infrared readings also from the side of the bin. However, this measurement approach suffers from similar deficiencies as it relies upon the temperature differences of the side of the bin. Unfortunately, the solids level may not rise and fall significantly at the side since the solid empties from the center of the conical bin. Another obstacle to this method is that the temperature may fluctuate significantly due to changes in ambient temperature (i.e., amount of sunlight, and temperature drops from day to night). Therefore, it can be difficult to take accurate and reliable measurements using such an approach. Yet another method of determining solid levels is to use “radar on a rope” technology. However, the dielectric between the solid material and liquid relied upon with this method may not be substantial enough to register an accurate reading, which could prevent reliable measurements.
Accordingly, a need exists for improved apparatus and methods for reliably and accurately measuring the level of solid materials in a flooded bin.